Core body temperature is an important indicator of a person's health. Traditionally non-invasive measurement of body temperature is based on oral, rectal, tympanic (ear), or axial (armpit) thermometers. Typically these provide a single temperature measurement per use and are not used to provide long-term monitoring of a patient's temperature. More recently, clinical thermometers based on the measurement of skin temperature over the superficial temporal artery of the forehead have appeared. The current implementations of these thermometers are as hand-held wands that are manually scanned across the forehead region. For long term monitoring of body temperature a thermometer that is unobtrusive and can be left affixed to a patient is needed.